Sometimes a silly idea can lead to a fascinating exhibition even as the silliness still shows through. When I first heard about “La peinture après l’abstraction,” documenting work done in Paris between 1955 and 1975 by five artists as unlike as Simon Hantaï, Jean Degottex, Martin Barré, Raymond Hains, and Jacques de la Villeglé, I thought the project utterly crackpot. I still think so; Degottex’s inclusion shows how little thought went into the mix. But the beauty is that Degottex’s oeuvre inadvertently serves as a repoussoir: The contrast his work provides helps demonstrate what the four others